Pet booster seat



FIG. 1 is a perspective view of a pet booster seat according to our design;

FIG. 2 is a front view thereof;

FIG. 3 is a back view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof,

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The broken lines are for purposes of illustration only and form no part of the claimed design. 

The ornamental design for a pet booster seat, as shown and described. 